From Friendship to Betrayal
by Dagny T
Summary: She had always been his favorite cousin. Through everything their family had put them through, they stuck together. But as they grow older and as secrets are revealed, they grow apart. Soon, love turns to hate  and friendship to betrayal.
1. Introduction

She had always been his favorite cousin.

Cissy was six years older than him and just plain mean. If he were to so much as ask for a game of Exploding Snap, she would turn up her nose and walk away as if he were making her sick. He liked Dromeda well enough, but she was still five years older than him, and was always too busy to play with her baby cousin.

But Bella was never too good or too busy for him. She was only two years his senior and they both were snubbed by the older kids, so they stuck together. Her parents came over to visit often, and even when they didn't she would come over by herself. On hot summer days they would go exploring in the woods behind the Black's summer manor and try to set fire to the twigs and shrubs, but hardly ever succeeded, being too young to have wands. In the winters, Bella would come over and they'd sneak through all the old rooms and secret passages of the Noble and Most Ancient House of Black.

They were both fascinated by their heritage. All the secrets, the mystery – they thought it was exciting. They would spend hours in the Black's library together reading histories of their family, trying (and often failing) to decipher the big words and understand the ancient tomes. They loved learning about the great wizards that had come from their families and all the spectacular things they had done. They even made friends with the portrait of Sirus' great great great Uncle Phineas in one of the unused bedrooms and got him to tell them stories of their family back in his day.

They were the best of friends. They were the _only_ friends each other had, so they always had each other's backs.

Whenever his parents did something particularly nasty (like curse him as a punishment, or remind him what an embarrassment of a son he was), he would send the family owl with a note to Bella and she would floo over right away.

"What did you do to make them mad this time?" she'd say quietly. He'd explain what he had said wrong or done wrong and how he was sure his parents were right: he was a huge screw-up, especially compared to little Regulus.

"They only say those mean things to you," she replied one time, "because you're not just some spineless, brainless worm like Regulus, who'll jump when they say jump. You are so much smarter and braver than any of them could ever be. You deserve so much better than your parents, Siri. Promise me you won't forget that."

He promised. "And Bella?" he added, "So do you."

Many nights Bella would floo into Sirius' room in the middle of the night. He knew that this meant Aunt Sophia and Uncle Ediclese were fighting again.

"What are they arguing about this time?" he would whisper as she sat at the foot of his bed.

"I don't know. But can I… can I stay here tonight?" she would reply, holding back tears. He would gather some extra blankets and pillows and they would lie down in two pallets on the floor. They'd both fall asleep holding each other's hand.

Once after one of these nights, when he was nine and she was eleven, he woke up to find her chewing on her fingernails and staring worriedly into the fire. He sat up and she looked at him.

"I should probably get back. They might have noticed I'm gone," she added the last part optimistically. They never noticed she was gone. He shook his head emphatically and crossed his arms.

"Bella, don't go back! We can pack some food and steal my daddy's broom and run away together! We'll go to – to… to Romania! And we'll live with dragons! And we'll be away from our stupid parents that don't care about us, and we'll always be together!" His eyes shone bright with excitement at his new plan.

She laughed and smiled sadly at him. "Siri, we can't. I'm going to Hogwarts in the fall, I'm gonna' get my own wand soon and everything. Then I can finally do magic like Cissy and Dromeda, and I won't have to see my parents all year. It'll be great!"

He just looked down dejectedly, knowing he couldn't win. "Fine," he mumbled. She got up and returned home.

When September 1st dawned that year, Sirius begged his mother to let him go to King's Cross to see his cousins off. She begrudgingly said she'd take him, but only if he promised to let her cut "that god-awful rat's nest you call hair". He agreed to the deal, though he secretly thought his mother was punishing him cruelly.

They got to the platform just in time to watch Bella and her sisters cross the barrier. Sirius was awed at what they had done and ran away from his mother and headfirst through the wall. He easily passed through it and began searching for his cousin through the hordes of students and parents. He jumped up and down trying to see over heads and darted around families. He finally spotted her, lugging her trunk onto the train.

"Bella!" he shouted and ran toward her. She turned around and grinned.

"Sirius! I'm so glad you're here!" she threw her arms around him in a hug. "Oh, I'm really going to miss you!"

"Then don't go," he said, and pulled back. He fixed her with the sternest look his nine year-old face could manage. "Stay here with me. I can't handle Mum if you're gone, and I won't have anyone to reach the books that are really high up in the library, and you won't be able to go exploring with me, and you won't be able to help me make sure Mum and Daddy's coddling doesn't give Regulus a big head, and – and –" his harsh façade broke and he burst into tears, "I don't want you to go!" He looked down, ashamed that he was acting like such a baby.

Bella patted his head then lifted his chin so that he was looking up at her. "I'll write to you every week. And I'll be back in the summer and we'll have loads of exciting adventures together. We may even go to Romania and tame a couple dragons," she winked and he tried hard not to giggle. "Besides, in just a few more years you'll be coming to Hogwarts, too, and then we can rule the school together, ok? So cheer up and give me one of your Siriusly charming smiles."

He grinned up at her and she grinned back. They hugged one last time, then she boarded the train and was gone.

She kept her word. Every Saturday, Sirius would receive a letter from Apollo, Bella's owl. She told him she had been sorted into Slytherin, just like Cissy had been. She had made some friends – Eleonore Nott, Zachary Zabini, Illiadora Goyle, and Rodolphus Lestrange. She said that she was really good at Potions and Defense Against the Dark Arts and a lot of the kids looked up to her. She was having a blast. He would write back. He would tell her about how he recently got in trouble ("_You should have seen the look on Mum's face when it exploded!") _or his latest punishments ("_They didn't let me have breakfast, lunch, or dinner yesterday. They said I didn't deserve it"_). To him, it felt like forever until summer came, but it finally did.

Sirius had been pacing in his room excitedly all day, hardly able to put up with the anticipation. It was the day Bella was supposed to arrive home. She didn't arrive until six o'clock. His bedroom fireplace crackled with green flames, and she stepped out smoothly.

"Bella!" he ran and smothered her in a hug. When he stepped back, he looked at her. There was something different about her. She stood a bit straighter than she had before she left, and she didn't look as timid. There was a slight air about her, too, and it took a while for Sirius to realize that it was confidence.

"So, how's my favorite cousin?" she said with a smile. They spent all night locked in Sirius' room, swapping stories. Bella entertained him by levitating his books around the room and making two pillows wrestle each other.

"But Dromeda says you're not supposed to do magic outside of school until your seventeen!" Sirius exclaimed through giggles.

"Well, you aren't, but Illiadora told me that if your in a house where adult wizards live, they can't tell if you're doing magic or not," Bella explained. He was proud that she knew so much – he was proud that she still wanted to be his friend, even though she knew so much now.

Bella didn't get up to leave until two in the morning. "They might miss me," she said, and he caught the hopeful gleam in her eye.

"Yeah, maybe," he said, but they both knew it wasn't true. His Aunt Sophia and Uncle Ediclese weren't very nice, and Sirius didn't like them at all.

Aunt Sophia was a tall, regal woman with golden hair and gray eyes. Cissy was the spitting image of her mother in looks _and_ personality. Uncle Ediclese was short and muscular. His blonde hair had specks of gray in it and his ice blue eyes were cold and emotionless. They frequently came over with Bella, and he saw them talking with his parents a lot, but he had a feeling they didn't like his parents much. Actually, he didn't think they liked anyone very much. They didn't like Sirius or Regulus; whenever they saw either of the boys they would order them to get out of the room as if they were vile creatures. They paid virtually no attention to their daughters, and everyone knew that this was because Uncle Ediclese had wanted a son and was continually disappointed that his wife had only produced daughters. They didn't even like _each other _very much.

They were constantly fighting. Bella didn't like it when her parents fought; it kept her up at night and sometimes gave her nightmares, which was why she would spend the night at Sirius' house a couple nights a week. Sirius loved Bella, and hated them for what they put her through and how little attention they gave her. Over the years there had been many time Bella had had to stop Sirius from throwing things at her parents or calling them names no seven or eight year old should know, and a few times she hadn't succeeded.

But Bella and Sirius didn't let Aunt Sophia and Uncle Ediclese dampen the mood that summer. Bella also hadn't lied when she said they would have adventures this summer (though they never did go to Romania). They got into more trouble that summer than they had all year, mostly thanks to Bella's wand and ability to do simple magic. You could find them hiding in secret compartments in the walls of Sirius' house and levitating things to fly around his parents' heads. They'd trick Regulus into eating chocolates Bella had bought from Honeydukes then watch his head shrink to the size of an egg (Regulus was always too embarrassed to tell their parents what had happened).

A few times they caused so much trouble that their parents would lock them up in their rooms for full weeks. That, of course, didn't stop them from sending Apollo between their houses with messages. One week they even came up with their own way of writing, so that if their parents ever found any of the messages they wouldn't be able to read the horrible names the kids had called them.

One night, Bella couldn't sleep. Her parents were fighting again, so she got up to floo over to Sirius' house. Then she thought she heard her father say her name. She wrinkled her brow and tiptoed out of her room and downstairs. As she walked she thought she heard Cissy and Dromeda's names too. She was the only one there to hear it, though, because Cissy had graduated school last year and no longer lived there and Dromeda was spending the night at some friend's house. Bella crouched down behind the living room couch, where she had a full view of where her parents were standing in the dining room.

"Ediclese! How dare you bring them into this! It's not my fault that you couldn't produce a proper heir the first time, and now you're unable to produce anything at all –"

"You're the one who spawned the last two! That Andromeda goes around socializing with Mudbloods! And Bellatrix is nothing but a lousy troublemaker; she'll probably end up being just as bad as her Mudblood-loving sister. They will never be true Blacks, never!"

"You're the one who told me to sleep with Elphius. We're not even sure of his bloodline! He could be a halfblood for all we know! And do you know that people are whispering about us? They can't understand why Andromeda and Bellatrix look nothing like their parents. I've heard people saying I'm a whore and I have some secret lover!"

"You're the one who insisted we keep the brats, Sophia! We could have just stuck them out on the streets and said you miscarried, but no, we had to keep them!"

Bella didn't hear her mother's offended reply because she was already halfway up the stairs, running back to her room as fast as she could. Ediclese's words kept echoing through her head: _"They'll never be true Blacks… never be true Blacks… never!" _She threw the floo powder into her bedroom fireplace and gasped, "Sirius' bedroom!"

Sirius heard the flames roar and glanced at the clock on his wall. It was four past midnight. "Bella?" he mumbled and sat up. "Bella, what's wrong?" he added when he saw her step out of the flames. He'd never seen her cry this hard before. She flung herself at him and buried her head in his shoulder.

"I'm n-not a Black," she said between sobs.

"What are you talking about? Of course you are! You dad is my dad's brother, so you're my cousin and definitely a Black," he said as he pet her hair. She looked up at him through teary eyes.

"No, Sirius. That's just it – he's not my father. Me and Dromeda aren't dadd— I mean Ediclese's daughters. Da—Ediclese wanted a son, but c-couldn't have kids after Cissy was born, so s-someone else is our f-father. I'm not a Black," she buried her face in Sirius' shoulder again.

"Bella, it doesn't matter! You're better than them! It doesn't matter to me who your dad is," he consoled her. "Besides, Black is just a name." She pulled away from him roughly.

"No, it's not! It's one of the oldest Wizarding names in existence. We – _you're_ related to some of the most powerful witches and wizards in history. Being a Black means you're _powerful_, you're _Pureblooded_. The Black name is practically royal, just ask Phineas!" she whispered harshly.

"Who cares about Pureblood and Wizarding families?" Sirius asked. The way Bella was talking, she sounded desperate, almost crazy. It was scaring him.

"I do!" she cried. Sirius looked down. He didn't understand why she was so upset; he'd be grateful if he found out he wasn't related to one of his parents. But he didn't say this, because Bella had never yelled at him before, and he didn't like it.

"I-I'm sorry, Bella. I just meant that… I still love you, no matter what," he said lamely. Bella smiled weakly at her ten year-old friend and scrubbed at her watery eyes with the back of her hand.

"I didn't mean to yell at you, Siri. I'm just… upset," she whispered and looked down at her trembling hands.

Sirius hated seeing her like this. He wanted her to smile or laugh, just to do something other than look so _sad_. So he did the only thing he could think of. He leaned over and placed a light kiss on her lips. When he straightened up her eyes were wide and he could see the blush creeping up her tearstained face.

"What was _that _for?" she whispered.

"I dunno. It just felt like the right thing to do," he said with a shrug. She smiled.

"It was."

He grinned, then busied himself making their pallets on the floor. The only thing that kept Bella from crying herself to sleep that night was Sirius' hand clasped around hers, squeezing it reassuringly every so often.

---------------------------------------------------

A/N: Bellatrix had been my favorite character for years, and while reading a fic about Sirius I got the inspiration for this. I hope you enjoy reading it as much as I enjoyed writing it!


	2. From Comics to Clubs

The next morning was Sunday, August thirtieth. Sirius woke up before Bella. He sat up in his blankets and untangled his fingers from her outstretched hand. He sighed and ran his fingers through his knotted hair. Last night had been much too much for his ten-year-old mind to handle; he was confused. Sure, he felt bad for Bella, how could he not? He knew that she deserved a family that loved her, just as she knew that he deserved the same, but Sirius didn't know why Bella was so upset. If the same thing had happened to him, he might have been shocked, but he would have accepted it; he already knew he wasn't a Black, at least not _really_, not by his parent's standards. As far as he was concerned, he would be relieved to find out he wasn't the spawn of Walburga and Orion Black.

"Siri?" Bellatrix muttered groggily as she sat up and rubbed her eyes.

"I'm right here," he said. She turned her head and looked over at him, a strange look overcoming her face. She blinked a few times, then realization dawned on her face. Her mouth fell open into a silent "oh". After a moment, she shook her head. "I… I've got to go. I'll… see you later," she whispered and quickly stood up.

"Wait! Bella…" Sirius started to say, but when she turned to look at him, he faltered. He'd never seen this look on her face before. Her eyes were impassive and her mouth was set in a straight line. She looked emotionless. Cold. Uncaring. He tried to ignore the shiver that ran down his spine. "See you later," he whispered. She stepped into emerald flames and was gone.

Sirius figured that Bella was still just in a state of shock. She'd come back to see him again before she left for school, and she'd be fine again. They'd play some pranks on Regulus and they'd laugh, and she'd be happy again. Yes. That's what would happen, and everything would be just fine.

But that's not what happened. The next night he was slipping between the sheets of his bed and he still hadn't seen Bella. _Maybe she's grounded_, he thought, but he knew that if she were, she would have owled him or found some other way to contact him. Sirius was beginning to worry that he wouldn't be able to say goodbye to her before she left. He slipped back out of bed and padded downstairs and into the kitchen. His mother was sitting at the table, absently stirring her tea, and reading _The Evening Prophet_.

"Mum?" he said slowly.

"What?" she barked, never taking her eyes off her paper.

"Could you please take me to the train station tomorrow to say goodbye to Bellatrix? I swear that I'll be good and I'll stop teasing Regulus and I'll let you cut my hair and I won't ask for anything else for a long, long, long time!" he said. He crossed his fingers behind his back, hoping that maybe his mother was in a good mood.

"Do you know what I found in your room yesterday?" she said calmly, eyes still on her newspaper.

"No…" he wasn't sure he liked where this was going. His mother finally looked up at him, her dark eyes piercing.

"A Muggle magazine," she said through gritted teeth. An alarm bell sounded in Sirius' head. A few weeks ago, Sirius' dad, Orion, had taken Sirius and Regulus to Flourish and Blotts with him. The only reason Sirius had been allowed to go was that Walburga refused to watch him. He and Regulus had each been given a few Sickles to spend while their father browsed the store. Sirius wasn't big on reading, so he wasn't planning to buy anything until he saw a display towards the back of the store. The sign said _American Muggle Comics_. Apparently, the store was trying to target different audiences or something. He picked up one brightly colored comic and began to flip through it. Soon, he was sucked into the world of Peter Parker and Mary Jane Watson. He immediately fell in love. He finished the first comic in the store and grabbed the second one, hoping to read it at home. That's when he realized what he was buying. He quickly grabbed a paperback copy of _The Fountain of Fair Fortune _and took it and the comic up to the counter. After buying both he stuck the comic inside the book where no one would see it. Apparently, though, someone had seen it.

"Oh… uh… How did that get there?" he said lamely, biting his lip. Walburga's only answer was to stand up and point toward the stairs. He glumly turned and marched back up to his room, his mother trailing behind him. She shut the door behind him and he heard her mutter a charm. He knew that this charm would lock the door and disable the floo to and from his bedroom.

"I'll tell Kreacher to bring you a pitcher of water. I'll let you out of there… eventually. Maybe this will teach you that a _proper _heir does not buy _Muggle comic books_." With that, Sirius heard his mother walk away from his door. True to his mother's word, Kreacher appeared in Sirius' room a few moments later with a cup and a large pitcher of water. He set them on Sirius' bedside table and looked at the boy reproachfully.

"You cause my mistress much trouble, Master Sirius. You ought to just behave yourself and act as a proper Black should. Master Regulus –"

"Yes, yes, I know what _Master Regulus_ would have done. Just shut up, Kreacher, and get out of here!" he shouted at the elf, who merely shook his bald head and disappeared. Sirius wondered how long a person could live without food. Was it two weeks? Three? They always let him out before that; the longest he had ever been locked in his room was five days – and that was when he had set Regulus' hair on fire.

He sighed as he got back into bed. He wouldn't be saying goodbye to Bella, but at least she would write him soon, right? Of course she would. She would write to him every week, just like last year. He was sure of it. He slowly drifted off to sleep, already excited about the letter he would soon get from Bella.

The next week went by uneventfully as Sirius patiently awaited Bella's letter. He was finally allowed to leave his room on Friday, and the first thing he did was go to the library. Over the summer he had finally grown almost as tall as Bella, and if he stood on a chair he could reach the top shelves. All of the books that his parents didn't want the kids to read were on the top shelves. He pulled a chair from the corner of the room and placed it in front of a bookshelf. He got on top of it and stretched out his arm until he grasped a dusty, leather-bound book from the highest shelf.

He sat down cross-legged in the chair and blew the dust from the tome. On the cover in golden cursive letters were the words, _The Dark Arts for the Practical Mind: A look into the theory behind The Arts._ He opened the book, but not before hastily grabbing a dictionary off the shelf.

Bellatrix sat on the common room couch, staring into the fire.

"Bellatrix, are you alright?" Eleonore Nott asked, plopping down beside her friend.

"I overheard Lucius talking to some fourth years yesterday," Bellatrix muttered vaguely, not taking her eyes from the fire.

"Yeah, he was talking about some club, right?"

"Yeah, a club for Purebloods. He said that joining would prove that you're truly loyal to your blood. A _true _Pureblood," Bella said.

"So?" Eleonore replied, twirling a lock of blonde hair on her fingers.

"I was thinking of joining. Well, when I'm older, because the leader doesn't even consider you unless you're at least fourteen." Bella finally looked away from the fireplace and up at her short, blonde friend. Her full mouth was set in a firm line and a look of purpose in her eyes — a look of determination.

"I'm not so sure that's a good idea, Bella, dear. After all, it is Lucius Malfoy who's talking about this club thing. I honestly don't trust Lucius as far as I can –" Eleonore was interrupted by a tall, ginger haired girl that had just walked up.

"Eleonore, you don't trust _anyone_," the girl snorted as she sat down in an armchair.

"I trust you and Bella! Well… Sort of. Kind of. Most of the time…" Eleonore replied, sniffing disdainfully.

"_Thanks_," Illiadora Goyle said dryly. "Why are we talking about Lucius anyway?"

"Bella was thinking about joining that club Lucius was advertising to the fourth years."

"Oh yeah, I was talking to Rodolphus and Rabastan about that. From what Rabastan says, it sounds pretty great. It's all about Pureblood power and all that. I think I might join it when I'm older too…" Illiadora tapped her chin pensively.

"_Illy! _Honestly, this whole thing sounds a bit shady. And really, I don't know about you, but I don't need some silly _club _to help me achieve great things, because people only inhibit you in the long run. But if you need some group to help you find a place in the world…" Eleonore shrugged her thin shoulders at Illiadora's glare.

"You're so intelligent, Eleonore, and if you weren't such a wench at times maybe you'd have more friends. And for your information, I wasn't saying that I need _anybody's _help—"

Bella wasn't listening to her two friends' spat. She was already lost in her thoughts, staring into the fire as she remembered what Lucius had said yesterday.

"_My fellow Slytherins," Lucius began. He was in the darkest corner of the common room, standing in front of a group of ten or so fourth years. His voice was low, but Bella could still hear him from her table a few feet away. "You shall be the youngest students to receive this proposition this year. You are all of noble heritage, and because of this, I am sure you want to, ah… preserve your way of life. I am sure you want to keep this world, our world… _pure_. I have recently joined a group, a club, if you will, that dedicates itself to keeping the wizarding world pure and conserving our families' ways of life. It is open to any Pureblood who wishes to join._

"_Our master, the leader of this club, is an extremely powerful wizard. I have seen firsthand the extent of his powers, and I can say with certainty that one day he will rule our world. He has promised that anyone who has been loyal to him shall receive power and grandeur beyond their wildest dreams, and I have no doubt that he can do this. He is still in need of more followers, though, and that is where you come in. Think of the pride it would bring to your family if you were to be in league with the most powerful wizard ever to live. It would prove that you are a truly noble Pureblood. You can only gain from joining this group," Lucius finished, treating the group to a smile that was known to make females swoon and cause teachers to forget that they were in the middle of scolding him._

"A true Pureblood…" Bella murmured to herself. Eleonore and Illiadora were too busy arguing to notice the dangerous glint in Bella's eyes. "A true _Black…_"


End file.
